what is test liner paper and test liner paper factory

Test liner paper is: Kraft liner is a paper which can be produced with 80% to 100% (virgin or first hand) pulp. If we produce paper which is made of 100% recyclable paper, it is called liner, and if it has two layers, it is called test liner. In Iran, when a slight percentage of high quality pulp is added to this type of paper, it is called pseudo kraft.I should be mentioned that the less virgin pulp is used in kraft paper, the closer will be quality of the product to test liner paper. Test liner paper is used in the production of corrugated sheet, and as per its quality it can be used both as the external and internal layer. The grammage of this type of paper ranges between 90 to 220 grams. The test liner paper which is used as the external layer of corrugated cartons has special technical specifications. For example, the external layer absorbs less water than the internal layer. The reason for less water absorption of the external layer is to support cartons from absorbing the environmental humid and to print on it better. The reason for the higher water absorption of the internal layer is to have better adhesion on fluting paper. Moreover, the test liner paper has proper surface resistivity for high quality printing.​